This invention relates to supports between wall studs and ceiling joists and, more particularly, relates to interjoist supports which can be inserted through relatively small ceiling openings, and manipulated to penetrate into adjacent joists.
The "after construction" mounting of hangers for ceiling fans, heavy lighting fixtures, potted plants, chairs, etc., has heretofore posed a serious problem in inaccessible locations. Standard electrical trade installation methods for ceiling electrical boxes in new construction will safely hold approximately a 10-pound static load. Ceiling fans, for example, present from 25-pound to 100-pound dynamic loads. Therefore, modifications must be made to safely hang heavier dynamic loads.
Adding ceiling fans or other heavy hanging fixtures in a two-story structure between floors is difficult. There are two options to effecting such an installation. The first involves the removal or modification of the ceiling covering to provide access. The second, and generally preferred method, involves accomplishing the entire installation through a standard 4-inch electrical box hole in the ceiling. Typically, these holes are located at various distances between ceiling joints.
The typical method for installing a heavy-duty hanger is to add a structural piece between the ceiling joists from which the electrical box and ceiling fan or other device is hung. If there is no top ceiling cover or if the ceiling cover is off, simple and various reliable installation methods are available. However, if the installation must be accomplished through the 4-inch electrical box hole, the hanger must be inserted through the hole and manipulated to form a structural member under compressive loading between the ceiling joists. Furthermore, compressive loading methods must consider and take into account moderate deformations of ceiling joists to retain compressive attachment integrity. Such deformations are caused by changes in load, temperature, humidity and material degradation.
In the prior art, some devices have been proposed for providing interjoist supports which can be installed through a small ceiling opening, and exemplary of such state of the art devices are depicted and described in the following U.S. Patents, namely: U.S. Pat. Nos. 3,518,421; to Codgill and 4,405,111 to Lennon. Codgill discloses a light-duty support of U-shaped sheet metal which is telescopic and has an end prong 16 at its opposite ends which are forced into opposed joists by spreading the support with a tool 24. While holding tool 24, locking block 30 is inserted to prevent the support from contracting. Apart from requiring the use of two hands and a special tool, the Codgill design is such that it could not be easily installed where the ceiling opening is at the edge of a ceiling joist because the special tool could not be inserted. There is also no provision for moderate deformations of the ceiling joists. Furthermore, under heavy loads, the prongs would tend to be pulled out as the load bends the channel 6.
Lennon, on the other hand, discloses a screw spreadable interjoist support which has lag screws at its opposite ends. The spreading screw forces the threaded ends against the joists so that the ends thread into the joists as their respective body portions are rotated. This construction would seem to prevent spreading of the joists, if the support is sufficiently strong. The lag screw penetration requires great amounts of torque for installation. The use of two wrenches and, accordingly, two hands, are required to effect installation. This design will not allow random location of the ceiling opening and probably would necessitate the elongation of the opening to properly locate the wrenches if the lag screws are very long. Furthermore, care must be exercised in not over extending the device to avoid damaging the ceiling joists.
Neither Codgill nor Lennon make provisions for hanging a heavy load such as a ceiling fan, for example, a J-hook bolt. Codgill only makes specific provisions for the electrical box, which Lennon indirectly indicates.
The prior art also discloses several other devices for installation between two vertical walls or posts. However, none are designed for installation through randomly located, small ceiling or wall panel openings, nor for accommodating hardware for attaching an electrical box or for hanging heavy loads. All require the use of two hands and/or some kind of tool or tools. The majority of these devices relate to light-duty expandable curtain rods which are not suitable for hanging heavy loads. These devices may be subdivided into three catagories. The first category includes rods composed of threaded portions and springs. Screw thread expandable rods without springs make up the second category. Finally, the third category utilizes only a spring to retain a telescoping rod in position.
Devices which are exemplary of the state of the art devices within the first category are depicted and described in the following U.S. Patents, namely U.S. Pat. Nos. 520,584 to Turner; 565,546 to Kingston; 670,585 to Fowler; and 2,199,851 to Culver. With the possible exception of Kingston, the force for compressive attachment to the posts or walls is provided by a spring forcing the ends of the rod apart. The threaded portions are relied on only for length adjustment and/or the extent of spring compression. Such designs are not suitable for hanging heavy loads thereon.
Kingston discloses a curtain rod with springs S at each end and a screw for extending the rod. Here, the force for compressive attachment to the posts or walls is provided by screws attached to a central member. Rotation of the central member relative to the end members forces the ends of the rod apart. Kingston also prefers that the springs be fully compressed to provide positive engagement of the end members. Thereafter the spring will continue to hold the rod in place even if the distance between the vertical support surface changes. If the springs are not fully compressed, then the compressive attachment force is provided only by the spring, as with the others in this category. The Kingston device if adapted for installation through a small ceiling opening would require an opening centrally located between the joists or studs. It also would not be suitable for hanging heavy loads thereon.
Devices which are exemplary of the state of the art devices within the second category are shown and described in the following U.S. Patents, namely: U.S. Pat. Nos. 404,841 to Johnson; 452,965 to Brothwell; 772,829 to Russell; 2,293,168 to Pirone; and 2,974,806 to Seewack. Here, the force for compressive attachment to the posts or walls is provided by a screw forcing the ends of the rod apart. None of these devices provide a following element capable of following or self-adjusting action in response to moderate deformations of wall studs or ceiling joists to retain compressive attachment integrity.
Most of these devices utilize prongs or teeth which are forced into the posts or walls as the rod assemblies lengthen to secure the devices against vertical displacement. Seewack utilizes rubber tips to create a friction fit to avoid marring the post or wall surfaces. The length adjustment in the Seewack, Brothwell and Russell devices are on one of the respective devices' ends. The Pirone device length adjustment is on a centrally disposed turnbuckle screw. None of the prior art devices can be used for randomly located ceiling or wall openings.
Johnson further requires the drilling of a hole into the post or wall prior to installation, which would be difficult to do through a small ceiling or wall opening. The hole receives a stem affixed to one end of the rod to provide a swivel means when the rod is rotated while the prongs on the opposite end of the rod are penetrating the contacted surface.
A device which is exemplary of the state of the art devices within the third category is depicted and described in Galbreath's U.S. Pat. No. 1,425,247. Here, the force for compressive attachment to the posts or walls and rod length adjustment are both provided by a spring forcing the ends of the rod apart. Such a device is totally unacceptable with respect to supporting heavy loads.
Of interest is Ganter's U.S. Pat. No. 596,108, which illustrates the wedge principle. A pair of reversely inclined wedges are attached to each end of a length-adjustable rod. The inner wedges are free to slide vertically on the outer wedges, so that a downward pull on the pole causes the inner wedges to force the outer wedges against the jamb, thereby tightly clamping the rod between the sides of the posts or walls. Heavy loads may reliably be hung on this device. However, this device is not suitable for a one-hand installation through a ceiling hole.
These, and other limitations and disadvantages of the prior art and especially of the aforementioned patents, are overcome with the present invention and commercially acceptable embodiments of a hanger assembly and the like are herein provided. Such embodiments are especially suitable for use by a person of only limited skill and capacity to easily install this hanger assembly of the present invention through a small ceiling opening using only one hand without the need for any tools. The embodiments of the present invention are also capable of use for installations which are beyond the capabilities of the prior art. More particularly, however, presently preferred embodiments of this invention are capable of following or self-adjusting action in response to moderate deformations of ceiling joists to retain compressive attachment integrity.